


Heat Of The Moment

by MyKinkIsPapyrus



Series: A First Time for Everyone [2]
Category: Undertale (Video Game)
Genre: Alternate Universe - Undertomb, Gender-Neutral Pronouns, Loss of Virginity, Mating Bites, Mating Bond, Mating Cycles/In Heat, Other, Reader has a vagina, baculum, monster reader, sans shows up but is not important
Language: English
Status: Completed
Published: 2018-12-12
Updated: 2018-12-12
Packaged: 2019-09-16 22:05:33
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,791
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/16962351
Author URL: https://archiveofourown.org/users/MyKinkIsPapyrus/pseuds/MyKinkIsPapyrus
Summary: As a monster, you go into heat like anyone else, but this time around, you have your sights set on a very tall and very handsome skeleton.





	Heat Of The Moment

You ran through the forest, dodging the traps. You weren't interested in those, but rather the monster who had set them up. You had had your eye on him for a few months, and now that you were in heat you knew exactly who you could recruit to assist you with it. As you knew he would otherwise become a potential source of interference, you made sure his wall of an older brother was asleep or off doing something in Waterfall or anywhere beyond Snowdin. 

Lucky for you, today was one of those days.

You spotted him, tending to one of his many vicious puzzle traps. The manic, hot buzzing beneath your skin urged you to trap yourself in one and have your scent seduce him into having his way with you however he pleased... but you knew that could come later. For now, you were going to have to take the lead. Just as he became aware of your presence - as you were not as quiet as you'd hoped to be - you lunged for him.

He managed to dodge you in the nick of time, causing you to slide slightly through the snow. The frozen sheet covering you did nothing to soothe the overwhelming heat in your skin, in fact, you were so warm by this point the snow slid off of you almost immediately. He rose a brow ridge at that, his skeletal visage imitating curiosity as best as it could. 

You stood perfectly still for a moment to let your intentions be known, lest he assume your attempted tackle was to initiate a fight rather than what you really had in mind. He took in your appearance; dilated pupils, heavy panting that came out almost as whines, and finally, he caught your scent which caused him to go rigid with surprise. 

Despite his rather attractive looks and charming bombast no one had ever considered him as a heat mate before, or a mate of any kind, and yet here you were, literally throwing yourself at him. 

You dropped to all fours suddenly, pupils dilating further. Carefully you edged forward, fully aware that if he wanted to not be involved, his experience climbing trees with his spindly legs as well as his raw, sheer speed outclassed you by leagues. He could easily escape and deny your unspoken request to have him bed you. 

But still, he stood there, entirely still, a look of intrigue played across his features. In an instant he had thrown himself at you, the momentum propelling you both through the snow. When you finally skidded to a stop he loomed over you, a hungry look in his eye lights. He was so close you could smell him, it was driving you wild. 

On instinct you flipped him over, straddling his slightly shocked form before violently rutting against his pelvis. This drew more pants from you, the sounds urging him to buck up into you. The stimulation pulled an almost howling sound from your throat before you slammed your mouth against his, the force opening his jaw enough for you to slither your tongue in. 

He summoned a tongue immediately, happily exploring your mouth. One of his clawed hands grabbed your ass, the other snaking its way into the fluff on your head, both of them holding you in place as he began lifting his hips up in tandem with your forceful grinding. 

All at once it stopped and you growled in response. He gave you a sharp look before eyeing his surroundings. You felt it then. You two were being watched. You couldn't see who it might be but you had a feeling there could only be two reasons for your sudden audience: Some of the insane forest-dwelling monsters thought they might target you for an easy kill or fuck seeing as how you were in heat. Or, the one that seemed more likely, your lover's brother didn't leave for as long as you thought he would. 

The very thought that the brute would show up to destroy your perfectly laid plans caused you to let out another growl, low and warning. Then you saw the glowing eyes behind Papyrus and deep into the darkness of the trees. It was him alright - Sans. At the sight of him, your claws dug deeper into the shoulders of his light armor and your thighs clamped down on the sides of his pelvis harder. 

As you continued to glare at the older skeleton, the younger one had had enough of lying in the snow and flipped you over before standing up, his claws in your ass digging deeper. He also noticed his brother at that point and rattled his bones in warning. 

"FUCK OFF, SANS, THEY'RE MINE." He hissed before climbing into a nearby tree. You never knew how tall and sturdy the trees outside Snowdin were but as he climbed ever higher you wondered where he was taking you. 

Soon you came upon a platform in the branches. Despite how unstable it appeared at first glance it was actually quite well secured. You knew because Papyrus unceremoniously dumped you onto it. 

"I APOLOGIZE FOR MY BROTHER BUTTING IN ON OUR FUN, BUT I PROMISE TO MAKE IT UP TO YOU." And in a second his teeth were harshly pressed against your mouth once more, your heat reigniting at double the insistence of before. 

You harshly grabbed his spine and began slowly dragging your claws along it. He let out a choked sound before his fingers went to his pants, deftly unfastening it, his other hand balling your shirt into his fist. The loose fabric you had chosen to wear around your legs today to grant easy access to him was hastily pulled up. 

The grip he had on your shirt allowed him to drag you onto his lap, his pants pulled down enough to expose his long bone cock to you. He freed his hand and used both of them to roughly grab your hips and smash your dripping slit against him. The friction drawing a loud moan from him and a yelp from you. 

You moved your hips back and forth along his length until he had enough teasing and used his grip on your hips to push you back, one hand letting go of you momentarily to pull his baculum completely out of his pants before he picked you back up and slammed you down onto him, his whole length spearing you. 

The feeling of him inside you was overstimulating, subconsciously you began stomping on the platform. The sound of it only edged him on as he began forcefully lifting you until he was almost completely out before slamming you back down, impaling you over and over on his cock at a brutal pace. 

You leaned forward, biting into his collarbone, fingers reaching under his armor to scratch at his ribs as he fucked you. The stimulation was proving to be overwhelming for him and in a few rather harsh thrusts he came. 

He tried pulling you off for a moment because of how sensitive he was but you held steadfast. You had a feeling the first round wouldn't last too long given his total lack of experience, so you figured it would be most beneficial to put him into heat as well. 

Delicately, you pulled the collar of your shirt to the side and brought his face to your exposed shoulder. He seemed to catch on to your game but wasn't enthusiastic about it, hesitating at the offer you were proposing to him. The heat was making you desperate, enough to even let out a pathetic sounding whimper and nuzzle his face with the top of your head. He relented with a sigh, annoyed that he couldn’t just wait for his own heat to be triggered by just being so close to you for an extended period of time.

He leaned towards your shoulder teasingly, deciding that if he was going to do it he would do it on his own terms. He slowly trailed his tongue along the unclothed part of your shoulder and the junction of your neck. His teeth grazing you slightly a few times before he suddenly bit down, intending to cause as little pain as possible. The second he tasted your blood, laced with the magic of your heat, his own was kickstarted. 

Suddenly you were pinned, Papyrus hovering over you. "I HOPE YOU'LL ENJOY THIS AS MUCH AS I HAVE SO FAR." He hissed out, as sincere as he could while overwhelmed with lust. As he spoke he was already thrusting into you, the fresh need to fuck you overpowering the sensitivity he still felt. 

His thrusts gaining momentum, he was soon able to fit completely inside you, filling you so entirely. But still, you wanted more, your legs subconsciously adjusting so they were as far apart as possible in a desperate attempt to have him fuck you even deeper. 

You growled at him as he shifted into a different angle, slamming into you in the best way possible. He rattled his bones in reaction to your walls clamping down on him, fucking you even harder than before, forcing a scream out of you at the feeling. You were getting close, you could feel it. 

He could feel it too, the way your tight cunt began to spasm around his cock. He was sure once you came he would follow right after, and with a few sharp thrusts you both did. He bit down once more on your shoulder to stifle the scream he was sure to let out from having cum twice in such a short time. You mimicked him, bringing your own teeth down onto his shoulder mostly to keep from biting your own lip off.

It took a few minutes for the high to wear off, and when it did you realize your heat was gone. You pulled back, a bit confused and saw that he wore a similar expression of confusion. A small realization dawned on his face.

“I THINK WE JUST MARKED EACH OTHER.” He pointed out as his summoned cock dissipated. You pushed yourself up and rested on your elbows as your head cleared enough to have those words process.

“Huh. I suppose we did.” He sat up completely to reach into a nearby basket where he kept a thick blanket. You trailed your eyes over him as he shook some pine needles out of the blanket and you decided you had chosen a fine mate. Finally he returned to your side on the loosely cloth-lined floor of his tree shack, before pulling the blanket over the both of you and wrapping his arms around you before you both drifted to sleep.


End file.
